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New Regulations Guide Testing of Pressure Relief Devices

In response to a petition filed by the Truck Trailer Manufacturers Association (TTMA), PHMSA has published new regulations to guide cargo tank users getting their Pressure Relief Devices (PRDs) tested.

Jun 02, 2016

In response to a petition filed by the Truck Trailer Manufacturers Association (TTMA), PHMSA has published new regulations to guide cargo tank users getting their Pressure Relief Devices (PRDs) tested.

The code requires PRDs, to be tested as part of their external-visual (V) or pressure (P) tests, but the existing language left some users confused as to the pressure requirements. If the cargo tank was an older 300 series no longer in production, the requirements might not even appear in the current regulations.

To address this, TTMA created a Technical Bulletin, TB-126 Bench Testing Reclosing Pressure Relief Devices to consolidate the best practices in the industry.

"As we were putting this together, it became apparent that the language in the regulations could be cleaned up," reported John Freiler, Engineering Manager at TTMA, explaining the motivation behind TTMA's petition.

The Final Rule creates a pressure vent bench test paragraph (j) under part 180.407 that both the visual- and pressure-test requirements now point to. In this, all the most common possibilities for cargo tanks and vent types are spelled out with opening and reseating pressures specified. The new rules are effective as of July 5th, 2016, but immediate compliance is allowed.